Siemens 6ES7321-7BH01-0AB0
SM 321 digital input, 16 DI, 24 V DC, diagnostics and hardware interrupt
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Siemens SIMATIC S7-300 SM 321 digital input module: 16 isolated inputs, 24 V DC, hardware interrupt, diagnostics and wire-break detection, isochronous mode, one 20-pole front connector.
- Manufacturer
- Siemens
- Manufacturer part no.
- 6ES7321-7BH01-0AB0
- Product family
- SIMATIC S7-300 PLC Modules
- Type
- Digital input module
- Category
- PLCs and I/O › Digital I/O modules
- Lifecycle
- Discontinued
- OEM successor
- Not stated
- Technical datasheet
- Data sheet
Technical specifications
- Manufacturer
- Siemens
- Manufacturer part no.
- 6ES7321-7BH01-0AB0
- Type
- Digital input module
- Application
- Digital input module
- Used with
- SIMATIC S7-300 rack (S7-300 backplane bus)
- Product function / Isochronous mode
- Yes
- Load voltage L+ / Rated value (DC)
- 24 V
- Load voltage L+ / permissible range, lower limit (DC)
- 20.4 V
- Load voltage L+ / permissible range, upper limit (DC)
- 28.8 V
- Load voltage L+ / Reverse polarity protection
- Yes
- Input current / from load voltage L+ (without load), max.
- 90 mA
- Input current / from backplane bus 5 V DC, max.
- 130 mA
- Encoder supply / Number of outputs
- 2
- Encoder supply / Type of output voltage
- L+ (-2.5 V)
- Encoder supply / Short-circuit protection
- Yes; Electronic
- Encoder supply / additional (redundant) feed
- Yes
- Output current / Rated value
- 120 mA
- Output current / permissible range, lower limit
- 0 mA
- Output current / permissible range, upper limit
- 150 mA
- Power loss, typ.
- 4 W
- Number of digital inputs
- 16
- Digital inputs / Input characteristic curve in accordance with IEC 61131, type 2
- Yes
- Number of simultaneously controllable inputs / horizontal installation / up to 40 °C, max.
- 16
- Number of simultaneously controllable inputs / horizontal installation / up to 60 °C, max.
- 16
- Number of simultaneously controllable inputs / vertical installation / up to 40 °C, max.
- 16
- Input voltage / Type of input voltage
- DC
- Input voltage / Rated value (DC)
- 24 V
- Input voltage / for signal "0"
- -30 to +5 V
- Input voltage / for signal "1"
- 13 to 30V
- Input current / for signal "1", typ.
- 7 mA
Show all 55 specificationsShow fewer
- Input delay (for rated value of input voltage) / for standard inputs / parameterizable
- Yes; 0.1 / 0.5 / 3 / 15 / 20 ms
- Encoder connection / Fixed current limitation for wire-break monitoring, min.
- 10 kΩ
- Encoder connection / Fixed current limitation for wire-break monitoring, max.
- 18 kΩ
- Cable length / shielded, max.
- 1 000 m
- Cable length / unshielded, max.
- 600 m
- Connectable encoders / 2-wire sensor
- Yes
- Connectable encoders / 2-wire sensor / permissible quiescent current (2-wire sensor), max.
- 2 mA
- Interrupts/diagnostics/status information / Alarms
- Yes
- Interrupts/diagnostics/status information / Diagnostics function
- Yes; Parameterizable
- Alarms / Diagnostic alarm
- Yes; Parameterizable
- Alarms / Hardware interrupt
- Yes; Parameterizable
- Diagnoses / Diagnostic information readable
- Yes
- Diagnoses / Wire break
- Yes; to I< 1 mA
- Diagnostics indication LED / Group error SF (red)
- Yes
- Diagnostics indication LED / Status indicator digital input (green)
- Yes
- Diagnostics indication LED / Encoder supply Vs (green)
- Yes
- Potential separation digital inputs / between the channels
- No
- Potential separation digital inputs / between the channels, in groups of
- 16
- Potential separation digital inputs / between the channels and backplane bus
- Yes; Optocoupler
- Isolation tested with
- 500 V DC
- required front connector
- 20-pin
- Width
- 40 mm
- Height
- 125 mm
- Depth
- 120 mm
- Weight, approx.
- 200 g
Technical documents (1)
Key features
- 16 digital inputs, 24 V DC, suitable for isochronous mode
- Parameterizable diagnostic and hardware interrupts, wire-break detection
- Input delay settable: 0.1, 0.5, 3, 15 or 20 ms
- Two short-circuit-proof encoder supplies
- Discontinued by Siemens on 1 October 2025; spare part only
About the Siemens 6ES7321-7BH01-0AB0
The Siemens 6ES7321-7BH01-0AB0 is the diagnostic version of the 16-channel SM 321. Unlike the standard 6ES7321-1BH02-0AA0, it raises hardware and diagnostic interrupts, detects wire breaks, has settable input delays (0.1 to 20 ms) and two encoder supplies, and is suitable for isochronous mode. Siemens's data sheet gives 16 inputs at 24 V DC (IEC 61131 type 2), a 20-pin front connector and 4 W typical power loss. Siemens's data sheet marks it as a spare part.
What is the 6ES7321-7BH01-0AB0 used for?
It reads switches, sensors and contacts into an S7-300 CPU where the program has to react at once to an input change or know when a sensor cable is broken.
Lifecycle and successor
Discontinued.
Before you order
What to photograph or confirm so the right unit is quoted.
Check the order number on the module: 7BH01 is the diagnostic version, 1BH02 the standard one. The front connector with the field wiring normally moves across to the replacement.
Other parts in the Siemens SIMATIC S7-300 family
Listed for reference. They differ from the 6ES7321-7BH01-0AB0 in rating, supply, interface or function and are not interchangeable with it unless Siemens says so. Match the part number on your unit.
| Product | Type | Lifecycle | Qty Available | Price | Action |
|---|---|---|---|---|---|
| Siemens 6ES7321-1BL00-0AA0SM 321 digital input, 32 DI, 24 V DC | Digital input module | Discontinued | On Request | On request | View |
| Siemens 6ES7321-1BH02-0AA0SM 321 digital input, 16 DI, 24 V DC | Digital input module | Discontinued | On Request | On request | View |
| Siemens 6ES7321-1FH00-0AA0SM 321 digital input, 16 DI, 120/230 V AC | Digital input module | Discontinued | On Request | On request | View |
| Siemens 6ES7322-1FH00-0AA0SM 322 digital output, 16 DO, 120/230 V AC, 1 A | Digital output module | Discontinued | On Request | On request | View |
| Siemens 6ES7322-1HF01-0AA0SM 322 relay output, 8 DO, relay contacts | Digital output module | Discontinued | On Request | On request | View |
| Siemens 6ES7321-1BH50-0AA0SM 321 digital input, 16 DI, 24 V DC, sourcing input | Digital input module | Discontinued | On Request | On request | View |
| Siemens 6ES7321-1FF01-0AA0SM 321 digital input, 8 DI, 120/230 V AC | Digital input module | Discontinued | On Request | On request | View |
| Siemens 6ES7322-1BF01-0AA0SM 322 digital output, 8 DO, 24 V DC, 2 A | Digital output module | Discontinued | On Request | On request | View |
| Siemens 6ES7322-8BF00-0AB0SM 322 digital output, 8 DO, 24 V DC, 0.5 A, diagnostics | Digital output module | Discontinued | On Request | On request | View |
| Siemens 6ES7322-1HF10-0AA0SM 322 relay output, 8 DO, 5 A, isolated per channel | Digital output module | Discontinued | On Request | On request | View |
| Siemens 6ES7323-1BH01-0AA0SM 323 digital I/O, 8 DI and 8 DO, 24 V DC, 0.5 A | Digital I/O module | Discontinued | On Request | On request | View |
| Siemens 6AG1321-1BL00-2AA0SIPLUS SM 321 digital input, 32 DI, 24 V DC, conformal coating | Digital input module | Discontinued | On Request | On request | View |
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